Electrical impedance devices



Oct. 24, 1961 u. WERTANEN 3,005,965

I ELECTRICAL IMPEDANCE DEVICES Filed Feb. 8, 1956 3 Sheets-Sheet 1 o-c SUPPLY $2,512;

L? ourpur 2 VERN/ER 40.74 LLICJ or 05L. OUTPUT 3 I INVENTOR.

Oct. 24, 1961 u. L. WERTANEN 3,005,965

ELECTRICAL IMPEDANCE DEVICES Filed Feb. 8, 1956 3 Sheets-Sheet 2 ll 1 5 E J INVENTOR. Whoa WWW.

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United States Patent 3,005,965 ELECTRICAL IMPEDANCE DEVICES Urho L. Wertanen, 14881 Manor, Detroit 38, Mich. Filed Feb. 8, 1956, Ser. No. 564,263 2 Claims. (Cl. 33324) This invention relates to electrical impedance devices,

and more particularly those wherein the reaction of distributed capacity and self-inductance, or mutual induction, of transformer action are the potentially dominant inherent properties employed characteristically in primary functions of such devices and their application; and somewhat more specifically, although not exclusively, to such arrangement of these devices which do not require that magnetic substance or material be present but may be introduced in proximity for modified character of operating conditions and their application.

In conventional structures of electrical impedance devices appreciable losses have hitherto been tolerated in the name of so-called leakage values in the absence of ways and means (defined as methods and resources) of employing them more fully.

It is, therefore, an object of this invention to provide anelectrical impedance device structure embodying special ways and means of employing the above mentioned properties and values more efficiently, advantageously and "with a greater degree of freedom than is found in conventional structures of prior art practice.

In carrying the said invention into effect, I may adopt the novel construction and arrangement of par-ts hereinafter described, by way of example, having reference to the accompanying drawings, wherein:

FIGURE 1 is merely a series of illustrative crosss'ec-tional views of physical arrangements in disposition of some tubular conductors being referred to later in the subject matter;

FIGURE 2 is a top plan layout view of an improved coaxial transformer construction made in accordance with the principles of the invention and with the insulated mounting and input and output terminals removed to illustrate details of the transformer proper electrically interconnected in the manner shown; FIGURE 3 is an illustrative end elevation of one form of a. transformer as anelectrical impedancefdevice constructed in accordance with the invention and incorporating some similar details as patterned in the structure of FIG. 2;

,FIGURE'4 is a side view of the device 0-: FIGURE 3,

and shown partly in cross-section on a plane indicated by accumulatively according to length, but strictly as a function' of the magnetic reluctance at and around their outer It is also commonknowledge that the only possible method to manipulate inductance is by .physioalarrangernent in disposition of the geometric factors at conductor surfaces My method of employing these facts in research developed the discovery of a new kind and character of electrical impedance devices.

Careful observation within the art discloses extremely common usage of coaxially insulated conductors. The art does not, however: teach my method of making an electrical impedance device by means of connecting a minimum of two coaxially insulated conductors in a sequence of their metallic continuity to form an electrical series coaxially following their common axis of length in the same relative direction of continuity; whereby, the conductors will carry a variable current in phase and instantaneously in the same relative direction coaxially following their common axis of length. As for example; employing conductors having a cross-sectional profile arrangement as illustrated for two coaxially insulated conductors in view b of FIGURE 1.

With that example and a variable flow of current the combined, reactions of the two in phase magnetic fields around the conductors will be clearly understood by careful-1y observing that the fields will be coaxially polarized in the same relative direction and coaxially compounded for coaxially increased reactance as impedance along the conductors in a manner which heretofore has not been disclosed within the Further, it should be observed from inductance and distributed capacity considerations as translated into terms of reactance and impedance that the invention has application in situations wherein the current is able, apt or likely to change in any conceivable manner. This applies equally for inductively disposed devices wherein the invention may be embodied in primary and secondary dispositions by allocation of at least two coaxially insulated conductors for either disposition.

In carrying out the principles of this invention many ways for economical gains will occur to the craftsmen and designers from the information given herein for that purpose.

This may then be developed, for instance, as illustrated in the sectional view 0 of FIGURE 1, wherein a third coaxially insulated conductor has been added. This is the basic requirement in development of this invention into the form of a transformer having a common axis of length for its conductors, and, wherein by means and method of connecting as previously described a two-toone ratio will be provided. The physical arrangement illustrated in section may also represent the disposition for a straight forward three-conductor series of reactorif desired.

A wide variety of devices may adopt such physical arrangement of insulated conductors as illustrated in View d of FIGURE 1, wherein the two concentrically insulated conductors may be connected to embody the invention, and the axially lateral conductors beingarranged in complex circuits as may be associated with embodiment of the invention. a

Referring to FIGURE 5 the schematic or simplified circuit diagram of a Colpitts oscillator will be recognized, employing impedance devices L2, L3 and L4 of this invention. These are within the tank section of the simplified oscillator circuit, and represent coaxial impedance elements of inductive react-ance-and load matching character, wherein L2 represents a coaxial impedance device with taps provided'for adjustment of impedance; and L3 =andL4 represent and comprise a coaxial translo-rmer as a four-terminal impedance element and load matching device. Other components of the oscillator circuit are indicated or self-explanatory from their position in the diagram together with their function in the circuit shown.

Those familiar with the art will be aware of the fact that applications of this invention are not by any means limited to this category of electrical circuits.

FIGURES 2, 3 and 4 illustrate characteristic details of one form of structural arrangement of an impedance device as designed and built by the inventor for so-called high or radio frequency induction heating applications.

13 indicates axially located secondary conductors, such as or" copper tubing, coaxially surrounded by insulation 13 of tubular form which in turn is within a coaxial tubular conductor 14, which may be of braided copper, surrounded by tubular insulation 14'. Similarly surrounding the insulation 14 is a further coaxial arrangement of a tubular conductor 15, in turn covered by insulation 15', and the outer coaxial conductor 16. With this coaxial arrangement of the tubular and circular conductor and insulation materials a very sturdy mechanical structure is obtained to withstand severe mechanical forces set up when high values of current and magnetic fields in operation create stresses tending to deflect, compress, elongate or otherwise distort the physical assembly. Also, with this disposition of the materials in coaxial concentricity, the potentially dominant inherent and desirable properties are completely at a designers disposal with a minimum of leakage values and limitations to be considered and dependent only on the quality of available material that may be involved in the application.

In the arrangement shown in FIGURE 4 there are a total of four identical coaxial unitsso that the transformer proper employs a total of sixteen tubular and circular lengths of electrical conductors in the coaxial arrangement described and illustrated, of which four are electrically connected in parallel as the internal axial secondary of the transformer, and twelve of the conductors .are electrically connected in series for the primary circuit of the transformer, shown symbolically as L3 in FIGURE 5 In the said FIGURES 3 and 4, 11 is a T type secondary output terminal connected to the tube extension 23 of a hollow connection header 1.7. Compression type fittings :8 are .used -to secure one end of each of the four tubular secondary conductors 13 (shown in FIGURE 2) to the brass connection header 17.

From the fittings 8 the tubular conductors 13 are continued into the coaxial arrangement of the primary con- .ductors 14, 15 and 16 and brought out atthe other ends thereof to like fittings 8 to secure the other ends of each of the conductors 1'3 to the hollow brass connection header 18 which, by its tubular extension 23, is fitted to the T type secondary output terminal 12. This comprises the transformer secondary arrangement between the output terminals mentioned, which for simplicity is shown symbolically at the output from the internal secondary L4 in the tank section of the basic oscillator circuit of FIGURES.

Referring again to the FIGURES 3 and 4, but predominantly using the side view of FIGURE 4, the primary circuit is a continuous ,metallic series in a sequence of details and continuity as follows: From terminal 3 and extension 22 with the lead 7 -.to the near endof the first unit conductor 16, its far end with a lead 4 to'the near end of the-second unit conductor 16, its far end with a leadA to ,the near end of the third unit conductor 16, its far end with a lead :4 to the near end of the fourth unit conductor 16, its farend with a lead 5 to the near end of .the -first unit conductor 15, its far end with a lead 4 to the near end of the second unit conductor 15, its far end with a :lead 4 to the near end of the third unit conductor"1S,-iits-farend withal-ead 4 to the near end of the fourth unit conductor 15, its far end with a lead 5 to the near end of the first unit conductor 14, its far end with a lead 4 to the near end of the second unit conductor 14, its far end with a lead 4 to the near end of the third unit conductor 14, its far end with a lead 4 to the near end of the fourth unit conductor 14, and its far end with the lead 16 and extension 22 to the terminal 6 to complete said primary circuit of the transformer.

It should be noted here that throughout the procedure of connections, in the series primary circuit just described, all of the conductors 14, 15 and 16 of each coaxially common unit are so connected that in operation with any flow of a variable current the respective magnetic fields around each coaxially common conductor will be polarized in the same relative direction for coaxially combined and increased reactance along the coaxial primary conductors; and for coaxially combined and increased transformer action upon the internal axially located secondary conductors 13. With this arrangement of the transformer it will be seen further that leakage reactance will be reduced to a vanishing point for all practical purposes in applications of the transformer.

Referring to the FIGURES 3 and 4 again; the assembly illustrated employs a sturdy fiat mounting insulation 1 with holes to receive the tubular primary and secondary terminal extensions 22 and 23, respectively, which are firmly attached by means of the threaded screws 2, studs 21 and nuts 20 being made up tight against flat washers 19. The complete assembly of the transformer proper may be located Within an insulating case 24 and be submerged in an insulating medium if desired; and internal cooling for the transformer may be introduced by passage of a cooling medium, as by employing the T type terminal fittings 11 and 12, which communicate via the internal tubular and hollow means referred to in the foregoing description. Additional cooling may also be arranged, if desired, by employing the threaded and tubular primary circuit terminal fittings which communicate through their hollow interiors into the near vicinity of the transformer proper.

In completing the coaxial transformer interconnmtions and assembly, the insulating material 9 was applied to obtain smooth surfaces and disposition of a neatly arranged assembly.

In making further practical tests of a comparative nature, this inventor performed a silver brazing operation of bonding two mating pieces of steel to form an assembly using, in one instance, the device described and, for purposes of comparison, ageneral design of induction heating transformer with which the time cycle of 18 seconds was required to heat, alloy, bond and to consolidate the operation. Upon substituting a transformer according to this invention, the next assembly to be brazed was destroyed due to excessive power input to the mating parts. However, with no-change other than a reduction of :plate voltage at the radio frequency generator from 8,200 volts to 7,150 volts, the previous satisfactory brazing operation was duplicated exactlyin every detail of appearance,quality and in the same timing of 18 seconds. The reduction of required input power in thisexample is typical of chiciency gained in favor of applications employing the coaxial structures of this invention.

This invention may be developed within thescope of the following claims without departing from the essential features of the said invention, and it is desired that the specification and drawing be read as being merely illustrative of a practical embodiment of the same and not-in'strictly limiting sense.

What I claim is:

1. Arrair core electrical impedance device comprising: an electrical series loop of two coaxially insulated conductors; a first terminal at the first end of the outer conductor; means connecting the other end of the outer conductor to the first end of the inner conductor; a second ter minal a h 9 1% end of the inner conductor; means "for supporting the device; and, at least one additional inner coaxially insulated conductor provided with terminal means at each end thereof.

2. An air core electrical impedance device comprising: an electrical series loop of two coaxially insulated conductors; a first terminal at the first end of the outer conductor; means connecting the other end of the outer conductor to the first end of the inner conductor; a second terminal at the other end of the inner conductor; means for supporting the device; and, a plurality of axially laterally insulated additional inner conductors provided with terminal means at the ends thereof.

References Cited in the file of this patent UNITED STATES PATENTS Roberts Oct. 10, 1939 Johnson Nov. 11, 1947 Doherty Mar. 20, 1951 Prache Feb. 16, 1954 FOREIGN PATENTS Austria Jan. 10, 1950 

